set T2 = the non empty T_2 TopSpace;
reconsider NTX = Top2NTop the non empty T_2 TopSpace as NTopSpace ;
take
NTX
; NTX is T_2
now for F being Filter of the carrier of NTX holds lim_filter F is trivial let F be
Filter of the
carrier of
NTX;
lim_filter F is trivial set S =
{ x where x is Point of NTX : F is_filter-finer_than U_FMT x } ;
for
x,
y being
object holds
( not
x in lim_filter F or not
y in lim_filter F or not
x <> y )
proof
let x,
y be
object ;
( not x in lim_filter F or not y in lim_filter F or not x <> y )
assume that A1:
x in lim_filter F
and A2:
y in lim_filter F
and A3:
x <> y
;
contradiction
consider x9 being
Point of
NTX such that A4:
x = x9
and A5:
F is_filter-finer_than U_FMT x9
by A1;
consider y9 being
Point of
NTX such that A6:
y = y9
and A7:
F is_filter-finer_than U_FMT y9
by A2;
reconsider x99 =
x9,
y99 =
y9 as
Point of the non
empty T_2 TopSpace by FINTOPO7:def 15;
consider G1,
G2 being
Subset of the non
empty T_2 TopSpace such that A8:
G1 is
open
and A9:
G2 is
open
and A10:
x99 in G1
and A11:
y99 in G2
and A12:
G1 misses G2
by A3, A4, A6, PRE_TOPC:def 10;
reconsider G19 =
G1,
G29 =
G2 as
open Subset of
NTX by A8, A9, Lm1;
A13:
(
G19 in U_FMT x9 &
G29 in U_FMT y9 )
by A10, A11, FINTOPO7:def 1;
(
U_FMT x9 c= F &
U_FMT y9 c= F )
by A5, A7, CARDFIL2:def 6;
then
{} in F
by A13, A12, CARD_FIL:def 1;
hence
contradiction
by CARD_FIL:def 1;
verum
end; hence
lim_filter F is
trivial
;
verum end;
hence
NTX is T_2
; verum